The shots are available now and are free to Loyola employees and students.
Loyola joins a handful of hospitals nationwide with mandatory policies to help protect workers and patients from the flu.
"Very few hospitals have taken this step. We are the first in the state of Illinois to take this step and it is the right thing to do. In the end, this will protect our patients and staff," Dr. Paul Whelton, of the Loyola University Health System, said.
Loyola's new policy does not apply to the new vaccine for the H1N1 flu virus. A spokesman says Loyola isn't making those vaccinations mandatory because of expected tight supplies.